The purpose of this first in human study is to determine the safety and feasibility of 1RG-CART therapy in patients with relapsed or refractory neuroblastoma. 1RG-CART therapy is a novel immunotherapy under investigation in which patients have their T-cells (a type of white blood cell) collected and modified in the laboratory, before they are given back to the patient. The T-cells are modified to express a chimeric antigen receptor (CAR) which targets disialoganglioside (GD2), a marker expressed on the surface of neuroblastoma cells.